Following the introduction of reserpine and chlorpromazine in psychotherapeutic medicine in the early 1950's, great effort has been expended in the search for other tranquilizing agents having improved biological profiles.
It has now been found certain indoles, and more particularly a series of 2-substituted-4-aryl-1,2,3,4-tetrahydropyrrolo[3,4-b]indoles, are extremely effective as tranquilizing agents.
The fused pyrrolo[3,4-b]indole ring system is relatively new in the chemical literature, the first successful preparation being reported by Southwich et al. J. Org. Chem., 25, 1133 (1960). These simple 2-substituted-1,2,3,4-tetrahydropyrrolo[3,4-b]indoles failed to demonstrate the antitumor activity for which they were prepared and tested.